#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

lambda = 0.5
r_sigma_a_to_sigma_b = 1

rhs = ( lambda^2 ) / ( 1 - lambda + r_sigma_a_to_sigma_b ) 

rts = polyroot( c( -rhs, +rhs, 1 ) )

(lambda/rts)^2